From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98431248F73; Wed, 18 Feb 2026 17:52:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771437140; cv=none; b=Fl9Mr65kdIOErtzHQkDmNeNY0cUudl2ZmJQ4GNjOJ/rj2OWqk2DZ5l+6Gt307G96dMYZRnRBi8/xXwxsKv4p6KOCY37MGUqRrfKkMK66OUJUV5AXfeDbEhfnTxeHCh2oorJ8OaY8ImHwTeen1chkDML6BelcIdZV/F1CRU5TcgY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771437140; c=relaxed/simple; bh=jkbcKySE2q3+0d2eltPFSdGhKmAGT605iAc5M4pcycM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=YBAZmflm3hddFh4oN6CIE/F3Q5tTMGk4lV2IzpJ7XNIv7+dTs6LDNPxgniMsHZNJcyWWVl7Of1pbiY1u2z2PVyPIKNpYw4vvgsyQsfV2h2w/BKWZqPmQ3DdGCSKmAqKr2kptIarkgoNuO8HgT4h0bQE8KWgS41mnNgU2ueZjeV0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=dR7+gJAU; arc=none smtp.client-ip=198.175.65.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="dR7+gJAU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1771437139; x=1802973139; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=jkbcKySE2q3+0d2eltPFSdGhKmAGT605iAc5M4pcycM=; b=dR7+gJAUV47+1f0466303UcxFqShOrEK/R8m4uzePGj53vmL1OPZcEcf RzSQTD1UxupeSHWsMwIRsno4c/pARkD3TUw+G4sco/30nIJH+rA3r8ZIq pr/9gSnc7IiU1Ve8T/g203wJBVrSLSrmhG6kheVOP1Rnyf4JQ9k8RnHjo 8EF1mJdA5/60D1z1wvE4/VYr20C0KOC0tt4vwf9xt43y2FVKJ7woIQOcQ O5dGMLw9uR0jXpCRmLGMyetW4NrbpTNaQ59oBkM41q6WL+50pZQpcOsRa 9KrOCBE4GKB+kzUGqBe5kAtSzuZKZR4OGwmDd0cadDC66ksJWbuQGIJ4/ Q==; X-CSE-ConnectionGUID: ViYXwyGnSbuq17rWbYqmBg== X-CSE-MsgGUID: q1vBF5l6RfeAlJ2hOuelDA== X-IronPort-AV: E=McAfee;i="6800,10657,11705"; a="89929881" X-IronPort-AV: E=Sophos;i="6.21,298,1763452800"; d="scan'208";a="89929881" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Feb 2026 09:52:18 -0800 X-CSE-ConnectionGUID: HzoCbuYnQ8+MIIwJFgzx7A== X-CSE-MsgGUID: 4bh8jUgXQXu+7QS562yTFQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,298,1763452800"; d="scan'208";a="212329200" Received: from aduenasd-mobl5.amr.corp.intel.com (HELO [10.125.109.212]) ([10.125.109.212]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Feb 2026 09:52:15 -0800 Message-ID: <0c464a2c-3722-45e5-9023-5a2fce8aa096@intel.com> Date: Wed, 18 Feb 2026 10:52:14 -0700 Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 7/9] dax: Add deferred-work helpers for dax_hmem and dax_cxl coordination To: Smita Koralahalli , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Ard Biesheuvel , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams , Jonathan Cameron , Yazen Ghannam , Davidlohr Bueso , Matthew Wilcox , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , Ying Huang , Yao Xingtao , Peter Zijlstra , Greg Kroah-Hartman , Nathan Fontenot , Terry Bowman , Robert Richter , Benjamin Cheatham , Zhijian Li , Borislav Petkov , Tomasz Wolski References: <20260210064501.157591-1-Smita.KoralahalliChannabasappa@amd.com> <20260210064501.157591-8-Smita.KoralahalliChannabasappa@amd.com> Content-Language: en-US From: Dave Jiang In-Reply-To: <20260210064501.157591-8-Smita.KoralahalliChannabasappa@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2/9/26 11:44 PM, Smita Koralahalli wrote: > Add helpers to register, queue and flush the deferred work. > > These helpers allow dax_hmem to execute ownership resolution outside the > probe context before dax_cxl binds. > > Signed-off-by: Smita Koralahalli > --- > drivers/dax/bus.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++ > drivers/dax/bus.h | 7 ++++++ > 2 files changed, 65 insertions(+) > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index 5f387feb95f0..92b88952ede1 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -25,6 +25,64 @@ DECLARE_RWSEM(dax_region_rwsem); > */ > DECLARE_RWSEM(dax_dev_rwsem); > > +static DEFINE_MUTEX(dax_hmem_lock); > +static dax_hmem_deferred_fn hmem_deferred_fn; > +static void *dax_hmem_data; > + > +static void hmem_deferred_work(struct work_struct *work) > +{ > + dax_hmem_deferred_fn fn; > + void *data; > + > + scoped_guard(mutex, &dax_hmem_lock) { > + fn = hmem_deferred_fn; > + data = dax_hmem_data; > + } > + > + if (fn) > + fn(data); > +} Instead of having a global lock and dealing with all the global variables, why not just do this with the typical work_struct usage pattern and allocate a work item when queuing work? DJ > + > +static DECLARE_WORK(dax_hmem_work, hmem_deferred_work); > + > +int dax_hmem_register_work(dax_hmem_deferred_fn fn, void *data) > +{ > + guard(mutex)(&dax_hmem_lock); > + > + if (hmem_deferred_fn) > + return -EINVAL; > + > + hmem_deferred_fn = fn; > + dax_hmem_data = data; > + return 0; > +} > +EXPORT_SYMBOL_GPL(dax_hmem_register_work); > + > +int dax_hmem_unregister_work(dax_hmem_deferred_fn fn, void *data) > +{ > + guard(mutex)(&dax_hmem_lock); > + > + if (hmem_deferred_fn != fn || dax_hmem_data != data) > + return -EINVAL; > + > + hmem_deferred_fn = NULL; > + dax_hmem_data = NULL; > + return 0; > +} > +EXPORT_SYMBOL_GPL(dax_hmem_unregister_work); > + > +void dax_hmem_queue_work(void) > +{ > + queue_work(system_long_wq, &dax_hmem_work); > +} > +EXPORT_SYMBOL_GPL(dax_hmem_queue_work); > + > +void dax_hmem_flush_work(void) > +{ > + flush_work(&dax_hmem_work); > +} > +EXPORT_SYMBOL_GPL(dax_hmem_flush_work); > + > #define DAX_NAME_LEN 30 > struct dax_id { > struct list_head list; > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index cbbf64443098..b58a88e8089c 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -41,6 +41,13 @@ struct dax_device_driver { > void (*remove)(struct dev_dax *dev); > }; > > +typedef void (*dax_hmem_deferred_fn)(void *data); > + > +int dax_hmem_register_work(dax_hmem_deferred_fn fn, void *data); > +int dax_hmem_unregister_work(dax_hmem_deferred_fn fn, void *data); > +void dax_hmem_queue_work(void); > +void dax_hmem_flush_work(void); > + > int __dax_driver_register(struct dax_device_driver *dax_drv, > struct module *module, const char *mod_name); > #define dax_driver_register(driver) \